The 21-year-old son of the late actor Dennis Hopper allegedly sexually assaulted a 15-year-old girl after luring her to his home in Venice Beach, California, with alcohol and DRUGS.

In a new civil lawsuit launched by the now 16-year-old girl's mother, it was claimed the actor ''engaged in sexually offensive conduct with her,'' including sexual intercourse, forced oral copulation and sodomy, after exchanging messages on Facebook for months, according to gossip website TMZ.

She is also said to have visited his home several times after being introduced by a mutual friend in February 2011.

A lawyer for the teenager, identified only as JANE DOE, says Henry ''preyed upon a young impressionable child, suggesting that he cared for her, luring her into his home with promises of alcohol and illegal drugs, and then repeatedly taking advantage of her youth and vulnerability''.

The girl's mother is suing for unspecified damages, and claims her daughter has had to seek psychiatric treatment.